Process of producing reduction products of carbon monoxide



Patented Sept. 29, 1931 UNlTED STATES PATENT. OFFICE AIIPKONS O. JAEGEB, OI CHICAGO, ILLINOIS, ASSIGNOR TO THE SELDEN COMPANY, 01' PITTSBURGH, PENNSYLVANIA, A CORPORATION OF DELAWARE.

rnocnss or rnonncme nnnncrron rnonncrs or cannon uonoxmn No Drawing.

stages according to the following reactions:

I C0 H2 CH O (-0. 7 caL; II CH O+H CH OH +27. 9 cal. III CH OH+H CHM-H 0 (+23. 9 cal.)

The physical agencies such as heat pressure and electrical discharges and the chemical catalysts which favor the reactions in the different stages are not the same and in order to produce maximum efliciency each stage should be carried out in the presence of the catalyst particularly suited to the reactions ar -'7'.- under the conditions of heat and pressure which are most favorable. In the ast no attempt has been 'made to reduce car on monoxide in stages at all, much less under the optimum conditions. for each stage. It constitutes one of the features of the present invention that the reactions for each of the three stages are caused to take place under the conditions of heat, pressure and chemical catalysts best suited to produce a maximum conversoin in each stage.

The reactions'are reduction or hydrogenation reactions and the catalysts to be used belong to the general class of reduction catalysts. I have found, however, that all reduction catalysts are not equally effective in the different stages and that it is necessary to accurately proportion and tune the catalysts forcach stage. Thus many reduction catalysts in concentration suitable for good yields tend to carry the reactions too rapidly through the stages and result in the formation of large amounts of methaneand side reactions. I have found therefore that it is necessary for best results to damp the activity of the catalysts in stages I and II and this constitutes a further feature of my invention.

For the purpose of the present invention,

Application filed September 9, 1925. Serial No. 55,393.

reduction catalysts may be divided into two ma1n,classes namely, strong reduction catalysts such as iron, nickel, cobalt and palladium, and. mild reduction catalysts such as copper, manganese, cadmium, zinc, magnesium, silver, gold and platinum. The elements may bedpresent in the form of the metals, their oxi es, hydroxides, salts, both simple and complex, and other compounds. In the case of zinc I have found that the best results are produced when part at least of the element is-in the form of zinc dust and this constitutes one of the features of the invention. Single catalysts may be used or mixtures of different catalysts.

I have found that even the mild reduction catalysts referred to above tend to cause too violent reactions, particularly at higher temperatures, for example, temperatures in exhols, ketones, higher 'aldehydes, acids and paraffines or mixtures of the above, and result in large yields of methane.

I have found that the activity of the mild reduction catalysts may be damped by mixing or combining these catalysts with catalysts having opposite functions, namely, oxidation catalysts. Among the oxidation catalysts I include those which are commonly used in the vapor phase, catalytic oxidation of organic compounds, such as compounds of chromium, vanadium, manganese, titanium, molybdenum, tungsten, cerium, thorium, These catalysts may be in the form of their oxides,-salts, both simple and complex, and other compounds. Single oxidation catalysts may be used as diluents to damp the activity of the reduction catalysts or mixtures of different oxidation catalysts may be so used. The catalysts may be used as such or may be coated on orabsorbed in carriers such as pumice, asbestos, kieselguhr, silica, porcelain, ,calcined magnesia, soapstone, roughened quartz, silicates and similar minerals.

The reduction and oxidation catalysts may be separately formed and the fragments mixed or arranged in layers or a articular mixture of best efiiciency can be ac 'eved by lead, tin,

uranium, zirconium and the like.

impregnating solutions of reduction and om"- dation catalysts into porous carriers.

The strong reduction catalysts. iron, nickel, cobalt and palladium shouldbe avoided or used in great dilutions. I have found that for certain purposes concentrations not exceeding 3% of the strong reduction catalysts may be used. It is not sufiicient to avoid the presence of strong reduction catalysts in, stages I and II at the beginning of the reactions but it is necessary to prevent deposition of any of these catalysts on the mild reduction catalysts during operation of the converter. It is thus necessary to prevent the the reaction of stage I, is carried out.

Owing to the fact that the reactions are equilibrium reactions, a high gas speed is desirable and should preferably be sufficiently high so that the volume of gas in the converter or converters is changed more than thirty times an hour.

The reduction can be carried out in separate converters for each stage using the temperature and pressure best suited for that particular stage and if necessary, supplying additional gas between stages. Thus stage I may be carried out in one converter, the gases compressed and forced into another converter mixed with additional hydrogen or hydrogen containing gases where necessary, reduced further in the second converter according to the reaction of stage II and finally reduced in a third converter with or without the addition of additionalhydrogen. The intermediate products, formaldehyde and methyl alcohol, may be removed in whole or in part. The reduction can also be carried out by combining two or more'stages in a single converter arranging the different catalysts in zones or mixed together or alternating zones of the various stages. The alternation of catalytic zones tuned to the different stages is of advantage particularly where stage I and stage II are combined since the reaction of stage II removes formaldehyde formed in stage I and thus upsets the equilibrium so that the further formaldehyde is rapidly formed by bringing the remaining gases into contact with more of the catalyst which is particularly suited for the reaction of stage I. 4

Stage I represents a slightly endothermic aeaaaee be determined incombination with the activity of the catalysts and the tmperature, as higher pressures not only tend to accelerate the reaction of stage I but they also tend to cause side reactions particularly condensation reactions of formaldehyde.

The proportions of carbon monoxide and hydrogen may be that of equal volumes but I have found that an excess of hydrogen is desirable as it not only pushes the equilibrium toward the production of formaldehyde in accordance with the mass action law but, due

to the peculiar character of the catalysts used,

the excess hydrogen does not exert any deleterious effects. I

The catalysts used consist of a mixture of mild reduction catalysts and oxidation catalysts and I have found that it is important that the latter should be in excess. The catalysts may be mixtures of oxidation and reduction catalysts or porous or inert carriers impregnated with a mixture of oxidation or reduction catalysts or finally one or more of the oxidation catalysts may be used as carriers for the reduction catalysts or vice versa. For some catalysts a very effective form is produced-by pressing finely powdered mixtures of the catalysts into the form of granules or fragments which show great efiiciency.

The presence of strong reduction catalysts should be avoided and if an iron converter or a converter consisting of a nickel alloy is used it should preferably be provided with a lining which is inert or a mild reduction catalyst, for example, copper linings may be advantageously used in many cases.

Formaldehyde may be recovered by sudden cooling, preferably by means of a water spray. Where the formaldehyde is not to be recovered the gases with or without addition of hydrogen may be directly introduced into a second converter after cooling and there further reduced to methyl alcohol or methane. The transformation of formaldehyde into methyl alcohol, according to the reaction of stage II, is a strongly exothermic reaction and accordingly excessive temperatures should be avoided particularly in combination withextreme pressures in order to prevent the production of side reactions and large amounts of methane. Where the reaction is carried out in a separate converter, the gases from the first stage, with or without separation of some of the formaldehyde stage compressor.

formed, are umped after cooling into a converter at big pressure and any added hydrogenor hydrogen containing gases which may be necessary may be directly pumped into the converter. In general, the pressures used in stage II are much higher than those in stage I but a wide variation is possible.

I have found that a very advantageous method of carrying out stages I and II is separate converters consists in connecting these converters to separate stages of a multi- The converter in which stage I is carried out is connected to the low pressure stage of the compressor and the gases from the first converter are fed into a higher pressure stage of the compressor together with any additional hydrogen which may be necessary and pumped into the second converter.

The catalysts used in the conversion of the formaldehyde to methyl alcohol consist in a mixture of mild reduction and oxidation catalysts but the proportions are different from those required in the first stage. In-

stead of an excess .of oxidation catalysts there should be an excess of reduction catalysts. The catalysts may be produced in any of the ways described in connection with the catalysts for stage I. Strong reduction catalysts should be avoided,,both in the original catalyst charge of the converter and the mater al of the converter Walls. taken to prevent the introduction of strong reduction catalysts in any form in the gas stream, as has been described in connection with stage I. The presence of strong reduction catalysts in extremely high dilutions may be tolerated but they should not be in excess of 3% of the total catalyst weight.

The methanol produced in stage II may advantageously be recovered from the exhaust gases by cooling followed by absorption in activated charcoal, silica-gel, or similar absorbents. Solvents of methanol may also be used. The reaction is preferably carried out in a rapidly moving gas stream which should have about the same velocity as in stage I, namely, suflicient to change the gas volume in the converter more than thirty times per iour.

Stages I and II may advantageously be combined in a single converter and this method presents many advantages. Formaldehyde is a relatively unstable compound whereas methyl alcohol is comparatively stable and by carrying out the reaction in a single converter, particularly where alternate layers or zones of formaldehyde and methyl alcohol catalyst are used, the formaldehyde formed is at once reduced to methyl alcohol and this permits the production of further amounts of formaldehyde in the next succeeding formaldehyde catalysts :zone, owing to the fact that the equilibrium is upset by the removal of formaldehyde. A similar effect Care should also be is produced by mixing the twocatalysts together. When the reaction is carried out in a single converter formaldehyde of course cannot be recovered and the main product is methanol.

Owing to theexothermic character of the reaction in stage II, it is of great importance to prevent/local over-heating of portions of the catalyst with a resulting decomposition, formation of side reactions and over-reduction. High gas velocities which have been referred to above are one-of the means which I have found to be advantageous in preventing the local over-heating and I have also found that the use of zones of catalysts of in creasing activity in the direction of the gas stream are very effective in preventing local overheating since the most active catalysts contact with the most nearly spent gases and the evolution of heat is evenly distributed over all of the catalyst. The endothermic stage I is further aided by the exothermic stage II. The increasing activity of catalysts in thedirection of the gas flow may be brought about in various ways. The concentration of the catalysts may be varied. Proportions of reduction and oxidation catalysts may be varied'to bring about an increasing percent age of reduction catalysts in the direction of gas flow and different catalysts of increasing specific catalytic activit may be used, for example, relatively weaff surface efi'ect catalysts such as activated carbon, coke and similar porous materials may be present with the first layer followed by layers containing elements and compounds of tin, silver, gold, I

lead, copper, cadmium, zinc, in the order named which represents a series of increasing activity. The oxidation catalysts may also be present in a series of decreasing activity in the direction of the gas flow and I have found that such a series for the methanol stage consists in thorium, cerium, zirconium, vanadium, titanium, molybdenum, uranium,manganese and chromium. Various combinations of these methods. may also be used but the net effect should always be an increasing reduction catalyst activity in the direction of the gas flow and care should be taken not to use reduction catalysts in excess in any layer used in stage I.

' The gases coming from the methyl alcohol converter with or without recovery of methyl alcohol can be further reduced to methane in a separate converter, wit-h or without pressure, at temperatures above 150 C. The strong reduction catalysts, iron, nickel, cobalt and palladium should be used in large quantioxide, silicon dioxide, titanium dioxide,

beryllium oxide, zirconium dioxide, molybdenum pentoxide, ferric oxide, vanadium trioxide, zinc oxide and uranium oxide. Both types can be partly or wholly in the form of their oxides, easily decomposed compounds, salts (simple and complex) or other compounds singly or in combination. The proportions of reduction and dehydrating catalysts may be varied but I have found that it is advantageous to use the reduction catalysts in excess.

Stage III is strongly exothermic and tends to proceed violently. A very rapid gas flow must be used when operating under pressure and preferably the converter should be cooled. I have found that a gas speed sufficient to change the gas volume in the converter at least thirty times or more an hour is desirable. If the above mentioned precautions are not taken the reaction may become uncontrollable and the catalysts become inoperative. 600 C. is the upper limit and from 200 C. up commercially practical reaction velocities are rendered possible. The gases before entering the methane converter may advantageously be so changed in composition by the addition of hydrogen or gases rich in hydrogen that the final gas after passing through the converter is pure methane.

The reduction of the carbon monoxide to methane in stages as described above presents theadvantage that the evolution of heat in the stages II and III is divided over the three stages and the danger of over-heating the catalysts in the converter due tothe very vioent reaction is lessened. Thus comparatively large amounts of gas can be caused to react in a definite time and high pressure can be used without involving great difficulties from a heat engineering stand-point.

The methane process can also be combined with the formaldehyde and methyl alcohol steps above described in a single converter by arral'iging the methane catalysts in zones or mixing with the formaldehyde and methyl alcohol catalysts. The activity of the catalysts may advantageously be increased in the direction of the gas flow as described above In connection with the production of the formaldehyde and methyl alcohol and the same methods or combinations can be used. The methane catalysts forma series of increasing catalytic activity as follows: iron, cobalt, nickel and palladium. A similar increase in activity in the direction of the gas flow can be carried out with the dehydrating catalysts by using this in the following series of increasing activity: zinc oxide, vanadium trioxide, ferric oxide, molybdenum pentoxide, uranium oxide, zirconium dioxide, beryllium oxide, titanium dioxide, silicon dioxide, chromous oxide, aluminum-oxide, thorium oxide. A variation of activity, by varying the concentration may also be used either alone or combined with the use of different dehydrating catalysts of increasing activity in a manner similar to that described in connection with the reduction catalysts. Methane catalysts may also be used with inert cementing mixtures such as albumen, sugar, dextrine or catalytically active cementing materials such as potassium or sodium waterglass, silica-gel or by a solution of alkali metal carbonates or hydroxides on inert carriers such as pumice, quartz, porcelain, earthenware, asbestos, kic selguhr and the like. Granules or fragments may also be formed by molding or pressing mixtures of catalysts and carriers in a finel divided state.

When the reactions of stages I, II and III are carried out in separate converters with varying pressures, the converters may advantageously be connected to various stages of multi-stage compressor. Circulating pumps may, of course, also be used in connection with any single stage.

Other gases such as nitrogen, carbon dioxide, methane, rare gases of the air, and small amounts of oxygen are not harmful. The gases should, however, be free from contact poisons such as sulphur, arsenic, hydrogen phosphide and metal compounds which exert a deleterious action on the reduction catalysts. The efficiency of the catalysts in all of the stages can be greatly enhanced by using. catalyst carriers of great surface energy.

I have found that finely divided materials such as kieselguhr, colloidal silicic acid, as-

bestos flour, pumice flour, quartz flour or finely ground silicates having an average par-- ticle size of 20a or less when used as a carrier for the reduction and oxidation catalysts or reduction and dehydration catalysts greatly enhances their efficiency. In some cases the increase in efficiency amounts to 20% or more and finely divided carriers of this type may be considered as positive activators of the catalysts. I am not certain as to why the finely divided carriers exert this remarkable effect which appears to be much greater than that due to the mere increase in surface. I am of the opinion, however, that the colloidal character of the carriers, that is to say, the enormous surface compared to the volume of the voids between particles results in an increased gas pressure due to the surface energy of the particles and thus enhances the reaction which takes place in contact with the catalyst on the surfaces of the carrier particles. While I believe that the above is probably the true explanation of the increased effectiveness of the finely divided carriers having particles approaching colloidal size, I have been unable to prove this explanation rigorously and do not desire to limit my invention to any theory which may or may not subsequently prove to be true. A particularly effective method of impregnating finely divided carriers as described above, consists in the use of solutions of complex salts or compounds of the catalysts which are thus very evenly and finely distributed on the particles and on calcination leave the catalyst in an evenly distributed form having an immense surface.

The impregnated finely divided carriers are preferably formed into granules by pressing with or without a cementing material such as organic adhesives, sugar, dextrine and the like, or salts of zinc, lead or ma esium and potassium or sodiumsilicate. T e gran,- ules are dried and calcined and if excess alkali is present it may advantageously be washed out. It should be understood, of course, that the finely divided material may be used as part or all of the carrier and may be associated with more massive carrier fragments as a coating. It is also unnecessary to use exclusively solutions of complex catalyst compounds. or salts as impre ated media. ile such solutions are pre erable in most cases, other methods of impregnating the catalysts may be employed either sin ly or in combination with impregnation y means of solutions of complex catalytic'compounds.

The invention will; be described more fully in the following. specific examples but it should be noted that the invention is not limited to the details therein set forth.

Example 1 A converter is charged with a catalyst formed by mixing 100parts of ammonium vanadate, 100 parts of manganese carbonate and 25 parts of chromic acid with 500 parts.

of calcined kieselguhr. The mixture is preferably in the presence of suflicient moisture to form a soft dough or paste and this is treated with a solution of 25 parts of ammoniacal silver nitrate, 30 arts of cadmium nitrate,- 10 parts of zinc nitrate and 3 parts of platinum chloride in the presence of about 10 parts of magnesium nitrate and 20 parts of water glass solution. The mixture is worked over and thickened until it can be formed into granules. The catalyst is first heated to about 300-400 C. in a stream of air and then Eeduced with hydrogen at about 250- 300 A purified water gas which is preferably prepared by the gasification of 'wood charcoal, and'which contains about 48% hydrogen, 45.5% carbon monoxide, 4% nitrogen, 1% carbon dioxide and 1.5% methone is introduced into the low pressure stage of a compressor and compressed to about 5 to 10 atmospheres and heated to about 200300 C.

whereupon it is passed over the catalyst in a very rapid stream.

Formaldehyde can be recovered in a good yield by a sulficiently rapid cooling of the gas stream, particularly by means of a water spray. Instead of removing formaldehyde t e gases coming from the converter may be cooled and additional hydrogen addedtobring the concentration of hydrogen to or more and the gases then compressed in a high .be' avoided in the resistance material, as

otherwise carbon is precipitated. Preferably a current of low voltage and high amperage is used in order to simplify the problem of insulation. The heating may also be carried out by means of a high pressure coil or helix which is lined with copper on the outsidev and is built into the converter. Water under pressure or mercury or other suitable liquids may be used and are heated to the necessary temperature and pumped through The coil serves also to remove heat the coil. of reaction after the process is once started and this is a further advantage of the coil method of heating.

The catalyst is prepared as follows:

The first layer of catalyst consists in a mixture of 200 parts of kieselguhr, 20 parts of short fibre asbestos and 5 parts of dextrine to which is added an ammoniacal silver nitrate solution equivalent to 8 8 parts of silver oxide and an ammonium vanadate solution corresponding to 46 parts of V 0 After evaporating the excess water the paste is formed into granules under pressure and dried. The next layer consists in 102 parts of molybdic acid, 98 parts of manganese oxide, 53 parts of lead oxide and 180 parts .of zinc dust, which are mixed in a moist state and pressed into granules. The next layer is prepared by coating 264 parts of cadmium oxide with 180 parts ofchromic acid in solution and treating with ammoniumvanadate containing 5 parts of vanadic acid. After evaporating the excess water the mixture is pressed into granules, using starch as a bindor if necessary. A layer of 138 parts of zinc dust, 52 parts of zinc oxide and 55 parts of chromium oxide follows. formed by mixing the moistened pasty mass, drying and pressing. Then follows a double layer of 84 parts zinc oxide, 64 parts zinc dust and 100 parts of'chromic acid mixed with i 200 parts of kieselguhr formed and dried.

The highly compressed gases from the formaldehyde converter are passed over the above described catalyst in the high pressure converter at about 300 to 400 C. at a high rate of speed. Preferably the gas speed should .be high enough so that the volume of gas in the converter is changed more than thirty times per hour. The exhaust gases on coolshou].

ing under methyl alco 01. The gaseous methyl alcohol remaining in the exhaust after cooling may be absorbed in activated carbon or slmilar absorbent.

The remainin gas can be returned to the first converter a ter adjusting its composition or it may be partiallyl or wholly passed into a third converter wit or without methyl alcohol. A considerable amount of additional hydro en should be added and thegases 5 pass over a contact mass consisting in a layer of 100 parts of bauxite and 110 parts of reduced iron cemented with water glass, then through a layer consisting in a mixture of 120 parts of nickel carbonate and 10 parts of aluminum oxide impregnated into 100 parts of pumice fra ents followed by a layer of 100 parts of t orium oxide fragments impregnated with 3 arts of palladium and 10 parts of nickel nitrate. A further layer'of 150. parts of kieselguhr or colloidal silica impregnated with 30 parts of nickel applied in the form of nickel ammonium nitrate and 15 parts of aluminum oxide applied in the form of sodium aluminate. The pressure may advantageously be from 2 to 5 atmospheres and the temperature from 250 to 400 C. The product is mainly methane.

Example 92 A high pressure converter which may be advantageously formed by a plurality of steel tubes shrunk onto each other is provided with an inner lining of aluminum and contains the following catalyst layers:

1. 200 parts-of kieselguhr and 18 parts of silver vanadate thoroughly mixed with 100 parts manganese dioxide and 6 parts of dextrineand formed into fragments.

2. 100 parts of thorium oxide coated with 9 parts of copper and 10 parts of zinc produced by evaporating complex ammonium salts of copper and zinc nitrate on the thorium oxide fragments.

3. Contact layers as described for the methyl alcohol converter in Example 1.

A as mixture of 20%-35% carbon monoxide and 65%85% hydrogen and containing less than 5% oxygen is passed through the converter at a temperature of 200-450 C.

and under a pressure of 250 atmospheres.

. The cover of the high pressure cylinder after charging with catalyst may advantageously be pressed into a conical packing by hydraulic pressure and then screwed tight. The exhaust gases contain large amounts of methyl alcohol and can be worked up to methane in a further converter as described in Example 1 or the methyl alcohol may be recovered. In the latter case, the remaining gases may advantageousl be recirculated with suitable additions 0 fresh gas.

Instead of the layers of methyl alcohol catalysts described in Example 1, the following ressure give excellent yields of contact layer can be efliciently used as the third layer in the converter. 130 parts of cadmium oxide, 220 parts of lead oxide,'200 parts of chromic acid and potassium silicate in amounts less than those corresponding to 100 parts KOH are mixed thoroughly with 300 parts of kieselguhr dried at 200 C. in carbon dioxide current. The dried mass can be freed from alkali by washing with water and may then be dried again and broken into fragments. A further excellent contact layer is formed by a mixture of 130 parts cadmium oxide, 10 parts zinc dust, 200 parts chromic acid, mixed with potassium si icate solution containing not more than 100 parts of KOH kneaded warm with 300 parts of colloidal silica and then heated to incipient sintering. Afterocooling, the mass can be freed from alkali and is broken into fragments.

E wample 3 A high pressure converter, provided with an aluminum lining in the inner tube, is charged with the catalyst mentioned in Example 2 and further with a deep layer of catalyst as described in connection with the methane converter in Example 1, and a mixture of 25 volumes of carbon monoxide and 7 5 volumes of hydrogen is passed through at a pressure of 20 atmospheres and 300 0., the gas speed being exceedingly high. The excess reaction heat can be efiectively removed by a cooling coil through which water is pumped at high pressure, a good yield of methane resulting.

It will be seen that the present invention provides a novel and improved method of reducing carbon monoxide operating on a different chemical principle than has been hitherto employed. The invention also in cludes improvements in each of the three stages of reduction and these improved stage reactions, as Well as the combination of stages, are included in my invention.

A further important advantage and feature of the present invention consists in the highly efi'ective catalysts used in the various stages associated with or impregnated on finely divided material having an average particle size of 20 1. or less. The impregnation of these finely divided carriers wholly or in part by solutions of complex compounds or salts of the catalytic elements constitutes a further advantage and feature and produces a catalytic layer on the carrier particles which is of great uniformity and homogeneity and is exceedingly effective in the reaction.

In the claims the expressions mild reduction catalysts, strong reduction catalysts, oxidation catalysts and dehydration catalysts are intended to include the compounds of the chemical elements referred to under these terms in the specification, or the elements themselves, singly or in combination.

What Is claimed as new 1s:

assesses 1. The method of producing formaldehyde which comprises causing carbon monoxide to react with hydrogen-containing gases in the-presence of mild reduction catalysts only whose activity has been damped by association with oxidation catalysts, the amount of oxidation catalyst being sufiicient to ensure the production of formaldehyde.

2. The method of producing formaldehyde which comprises causing carbon monoxide to react with hydrogen-containing gases in the presence of mild reduction catalysts only associated with an excess of oxidation catalysts.

3. The method of producing formaldehyde which comprises causing carbon monoxide to react with hydrogen-containing gases in the presence of an excess of mild reduction 'catalysts whose activity has been damped by association with oxidation catalysts only and in the substantial absence of strong reduction catalysts.

4. The method of producing formaldehyde which comprises causing carbon monoxide to react with hydrogen-containing gases in the presence of mild reduction catalysts associated with an excess of oxidation catalysts and in the substantial abscnceof strong reduction catalysts at the beginning of the reaction and preventing the later introduction of substantial qualities of strong, reduction catalysts in any form.

5. The process according to claim 1, in which at least some of the reduction catalysts serve as carriers for the oxidation catalysts.

6. The method of producing formaldehyde which comprises causing carbon monoxide to react with hydrogen-containing gases in the presence of mild reduction catalysts andstrong reduction catalysts associated with an excess of oxidation catalysts, the strong reduction catalysts constituting not more than 3% of the total catalyst weight.

' 7. The method of producing formaldehyde which comprises causing carbon monoxide to react with hydrogen-containing gases containing a molecular amount of hydrogen considerably in excess of the carbon monoxide, the reaction taking place in the presence of mild reduction catalysts only whose activity has been damped with an excess of oxidation catalysts. 7

8. The method of producing formaldehyde which comprises causing carbon monoxide to react with hydrogen-containing gases in the presence of mild reduction catalysts associated with an excess of oxidation catalysts and subjecting the reaction gases to sudden.

cooling.

9. The method of producing formaldehyde which comprises causing carbon monoxide to react with hydrogen-containing gases in the presence of mild reduction catalysts associated with an excess of oxidation catalysts and suddenly cooling the reaction gases by means of a water spray.

10. The method of producing methyl alcohol from gases containing formaldehyde and hydrogen which comprises causing these gases to react in the presence of mild reduction catalysts whose activity has been damped by lzissociationof oxidation catalysts therewit 11. The method of producing methyl alcohol from gases containing formaldehyde and hydrogen which comprises causing the gases to react in the presence of mild reduction and oxidation catalysts, the reduction catalysts being in excess.

12. The method of producing methyl alcohol from gases containing formaldehyde and hydrogen which comprises causing these gases to react in the presence of strong reduction catalysts in amount less than 3% of the total weight of catalysts.

1 3. A method of preparing methyl alcohol WhlCll comprises causing carbon monoxide and hydrogen containing gases to react in the presence only of catalysts favoring the production of formaldehyde and causing the reacted gases containing the formaldehyde thus produced, without separation from the gas stream, to react with h drogen in the pres ence only of catalysts avoring the production of methyl alcohol.

14. A method according to claim 13, in which the activity of the catalysts in the gtages is increased in the direction of gas 1 5. A method according to claim 13, in which the activity of the catalyst in the sta es s increased in the direction of the gas flow increasing the concentration of the active catalyst com onents.

16. A met 0d according to claim 13, in wh1chtl 1e activity of the catalysts in the stages is increased in the direction of gas flow by the use of catalysts of progressively greaterspecific catalytic power.

17. A method according to claim 13, in which the gas velocity is at least thirty times the converter volume per hour.

18. Themethod of preparing methyl alcohol which comprises causing carbon monoxide and hydrogen-containing gases to react tion catalysts and oxidation catalysts, the

reduction catalysts being in such excess as to favor only the production of methyl alcohol.

19. The method of producing methyl alcohol which comprises causing carbon monoxide to react with hydro en-containing gases in the presence of cata ysts' favoring only the formation of formaldehyde and causing the formaldehyde so produced, without separation from the gas stream and in a separate stage, to react with hydrogen in the presence of mild reduction catalysts and oxidation catalysts, the reduction catalysts being in such excess as to favor only the production of methyl alcohol.

20. The method of producing methyl alcohol which comprises causing carbon monoxide and hydrogen-containing gases to react in the presence of mild reduction catalysts whose activity has been dam ed bythe association of an excess of oxi ation catalysts, causing the formaldehyde thus formed, without separation from the gas stream and in a separate stage, to react with hydrogen in the presence of mild reduction catalysts and oxidation catalysts, the reduction catalysts being in such excess as to favor only the production of methyl alcohol.

21. The method of producing methyl alcohol which comprises causing carbon monoxide and hydrogen-containing gases to react in the presence of catalysts favoring only the production of formaldehyde, introducing additional hydrogen into the gas stream, and

causing the formaldehyde without separation from the gas stream, and 1n a separate stage to react with hydrogen in the presence of mild reduction catalysts and oxidation tion catalysts being in suchrexcess as to favor only the' production of methyl alcohol.

23. The method of producing methyl alcohol which comprises causing carbon monoxide and hydrogen-containing gases which are free from catalyst poisons to react in the presence of catalysts adapted to favor oxide and hydrogen-containing gases to react in the presence of catalysts which favor only the production of formaldehyde and causing the formaldehyde without separation from the gas stream, and in a separate stage to react with hydrogen in the presence of mild reduction catalysts and oxidation catalysts, the reduction catalysts being in such excess as to favor only the production of methyl alcohol, the two reactions taking place in a single converter and the catalysts beingarranged in alternate zones.

20. Process of producing formaldehyde comprising heating equi-molecular quantities of hydrogen and carbon monoxide to an elevated temperature of less than 450 C. under a superatnlospheric pressure in the presence of .a nonbasic catalyst capable of causing the carbon monoxide and hydrogen to combine to form formaldehyde.

27. Process of producing formaldehyde eon'iprising heating equi-molecular quantities of hydrogen and carbon monoxide to an elevated temperature between 200 and- 350 C. under a superatmospheric pressure in the presence of anon-basic catalyst capable of causing the carbon monoxide and hydrogen to combine to form formaldehyde.

Signed at St. Louis, Mo., this 2d day of September, 1925.

ALPHONS O. J AEGER.

only the production of formaldehyde and causing the formaldehyde thus produced, without separation from the gas stream and in a separate stage, to react with hydrogen in the presence of mild reduction catalysts and oxidation catalysts, the reduction catalysts being in such excess as to favor only the production of methyl alcohol.

24. The method of producing methyl alcohol Whichcoinprises causing carbon monoxide and hydrogen-containing gases to react in the presence of catalysts favoring only the production of formaldehyde and causing the formaldehyde thus produced without 

